1. Field of the Invention
This invention relates to surgery and more particularly to an apparatus and method for total hip arthroplasty in a patient.
2. Background of the Invention
A total hip arthroplasty in a patient involves the insertion of a prosthetic stem into femur of a patient. The prosthetic stem is connected to a hip ball head through a metallic neck. The hip ball head and the metallic neck of the arthroplasty replace the head and neck of the femur of a patient. An acetabular prosthetic cup is mounted within the acetabulum of a patient for receiving the hip ball for completing the total hip arthroplasty.
A critical stage in the total hip arthroplasty procedure is the orientation of the acetabular prosthetic cup within the acetabulum of the patient. Typically, the acetabular prosthetic cup is orientated with respect to the anterior pelvic plane (APP). Various computer aided navigation systems have been devised for assisting a surgeon in orientating an acetabular prosthetic cup within the acetabulum of the patient.
In many cases, the anterior pelvic plane (APP) does not provide an accurate orientation of an acetabular prosthetic cup within the acetabulum of the patient. A small error in correctly identifying the anterior pelvic plane (APP) results in significant errors in the placement of acetabular prosthetic cup. In some instances, the pelvic position introduces significant errors in the placement of acetabular prosthetic cup. In other instances, the anterior pelvic plane (APP) is not a specific indicator for the placement of the acetabular prosthetic cup in a specific patient. Some in the prior art recommended the use of ultrasound in identifying anterior pelvic plane (APP). The use of ultrasound was done with the patient in a supine position. Unfortunately, the accuracy was diminished when the patient was moved into the lateral decubitus position. Other in the prior art recommend acquiring the anterior pelvic plane (APP) in the supine position prior to turning the patient to the side, but this can be impractical and increases the operative time with possible compromise to sterility.
Therefore, it is an abject of this invention to provide an improved method of aligning an acetabular prosthetic cup within an acetabulum of a patient through the use of a calculated acetabulum center axis.
Another object of this invention is to provide an improved method of aligning an acetabular prosthetic cup within an acetabulum of a patient that provides more accurate results than orientation with respect to the anterior pelvic plane (APP).
Another object of this invention is to provide an improved method of aligning an acetabular prosthetic cup within an acetabulum of a patient that may be incorporated in a computer aided navigation system.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed as being merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be obtained by modifying the invention with in the scope of the invention. Accordingly other objects in a full understanding of the invention may be had by referring to the summary of the invention and the detailed description describing the preferred embodiment of the invention.